Ball and rod mill



May 19, 1925.

F. M. cANDA BALL AND ROD MILL Filed Feb. 19, 1924 Y Y anvemtoz 77%. 06/7250,

affoznma Patented May 19, 1925.

UNITED STATES I FERDINA IN'D MORA CANDA, OF CHROME, NEW JERSEY.

BALL AND ROD MILL.

Application filed February 19, 1924. Serial No. 693,862.

To all whom it may concern Be it known that I, FERDINAND MORA CANDA, a citizen of the United States, residing at Chrome, in the county of Middle- 5 sex and State of New Jersey, have invented certain new and useful Improvements in Ball and Rod Mills, of which the following is a specification. v

This invention relates. to grinding mills 1 of the type known as ball mills and rod mills. These mills are usually of large diameter through which the material is fed and discharged continuously, and the contents of the mill Weighing many tons and 1 consisting of heavy loads of balls and rods subject the liner plates to very excessive shock in service, due to the impact of the A balls or rods against the liners. The plates must not only be subjected to the severe im- 2 pact shocks but they are also subjected to the constant wear due to the mass of steel balls and material continually grinding across their surfaces.

The object. of my invention is to provide 2 a construction permittin the use of a very hard gradeof steel (which for liner plates will afi'ord the maximum resistance to wear) and at the same time reduce to a minimum the breakage of the plates. In order to secure the desired hardness and wear-resistin qualities it is necessary to employ steed which is more brittle. I have overcome the difliculty by interposing a shock absorbing medium back of the liner plates and between the latter and the shell or casing of the ball mill. There must be no creeping or tangential movement of the individual plates and each plate must be rigidly anchored to the casing. I accomplish these results and secure the desired staunchness, providing 'a mill. having the maximum wear resistmg surface lining, at the same time maintaining the integrity of the brittle hard steel, by

bolting each plate'to the casing at a plurality of points with a shock or impact absorbing medium interposed between the plates and the casing.

In the following detailed description of one form of my invention I shall refer to the accompanying drawings, wherein Figure 1 is a transverse section through the cylinder of a mill constructed in accordposition with respect-to the shell by means ance with this invention and which shows the plates held in position by bolts.

. Figure 2 is a longitudinal median section therethrough. Figure 3 is an enlarged detailed section taken transversely through a portion of the cylinder wall.

1Figure 4 is a plan view of one of the liner p ates. I

In the drawings I have omitted the balls or rods andthe material to be ground in order to. more clearly show the construction. This cylinder is provided with-an outer 65 c'asing.or shell 10, and an inner liner con: sisting of a series of longitudinally extending liner plates 11, these plates belng interlocked at their edges and forming a circular series around the cylinder rigidlyheld in position by a plurality of symmetrically dis:

posed bolts 13.

Spaced inwardly from the shell between the shell and the liner there is provided shock absorbing means 12, which is here shown as consisting of a layer of elastic material, such as rubber, leather, felt and the like, the invention not being restricted to any specific form of such means, although on some accounts a layer or sheet of rubber is found preferable, owingto its peculiar resilient quality.

The liner plates are maintained in proper of the bolts .13, having their inner ends 5 countersunk into the liner plates, each bolt passingthrough the overlapping edges of two plates. It is'obvious that the liners need: not necessarily overlap to be bolted to the shell, and I illustrate only one form or design of linen commonly used.

With this arrangement disintegration of the liner due to the constant impact of the balls thereon is very materially lessened and the life of the liner is thereby prolonged. Harder steel havin increased wear-resist, ing qualities may fie used without undue danger andwith a minimum of loss due to breakage. Furthermore, the cost of maintenance is' correspondingly reduced and the life of the mill is prolonged by the elimination as far as possible of the excessive vibration due to shocks which are produced 1 in the pulverizing operation of the g nill.

It is obvious that engineers and others skilled in the art may change the specific construction shown without departing from the spirit of theinvention, the breadth of 5 the invention being interpreted by the scope of the claims.

Having thusdescribed the invention, what is claimed as new is:

1. In a ball mill, rod mill, or other grinding,mill, a metal shell or casing, a circumferential series of brittle hard steel liner plates bolted to the shell, and a resilient shock absorbing medium interposed between the plates and the shell.

2. In a ball mill, rod mill, or other grinding mill, a metal shell or casing, a circumferential series of hard tool steel wearing plates bolted to the shell and a resilient shock absorbing medium interposed between the plates and the shell.

In testimony whereof I aflix my signature.

FERDINAND MORA CANDA. 

